Open-hearth furnace



N. F. EGLER LSSQQ OPEN HEARTH FURNACE Filed April 50, 1951 5 Sheets-Sheet l v INVENTOR ha/mm 76%;76 m am Dec. 13, 1932. N. F. EGLER OPEN HEARTH FURNAGE 5 Sheets-Sheet 2 Filed April 50, 1951 INVENTOR Filed April 30, 1951 I5 Sheets-Sheet 3 INVENTOR Patented Dec. 13, 1932 f UNITED STATES PATENT OFFICE` NIKLAS F. EGLIER, OF MONESSEN, YPEINNSYIl/'ANIA OPENfHEARTH FURNACE Application filled .April 30, 1931. Serial N'o. 533,960.

In the operation of open-hearth steel furranged at opposite ends open to the furnace naces, fuel and air are admitted to the furnace chamber. Into the port 4 extends a nozzle chamber through a port or ports arranged at 5, through which fuel is delivered lin a jet one end of the chamber, and the gaseous proddirected through the portand into theV furucts of combustion find escape through a port nace chamber. The particular nature of the 55 or ports at the opposite end. Periodically fuel is not here important; suice it here t the direction of flow is reversed, and the port say that it may be a jet of oil or tar atomized which had been serving as the intake port bein a stream of compressedair or gas, or it comes the port for the outow of the products may be a jet of coal dust carried on such a of combustion, while the port which had been stream. The nozzle 5 is advantageously ar- 50 the outflow port becomes the intake. The ranged in the vertical mid-planeof the furvolume of the outgoing products of combusnace, and, with the structure of the present tion is vastly greater than that of the incominvention in view, it is conveniently spaced at ing fuel and air. This is due both to the an interval above the iioor of the port. Rischemical changes involved in combustion and ing vertically through the floor of the port on '35 to the elevation of temperature incident to either side of the nozzle 5 and opening into the combustion. Because of this condition, it port 4 are air uptakes 6, 6. Through these long has been a problem, how to fashion and uptakes streams of combustion-sustaining air, arrange the furnace ports to achieve in largpreheated in usual manner in the regenerator 0 est measure economyV of fuel, eficiency of chambers (not shown), enter the port and 7 operation, and durability of structure. This advance with the fuel to the furnace chaminvention consists in a port structure deber. The iame springs from the port at one signed to achieve good results of the nature end, and streams through the'furnace chamindicated. ber. The products of combustion pass out In the accompanying drawings, Fig. I is a through the port at the opposite end of the 75 view in horizontal section of the structure of furnace chamber. Periodically, by the opone end of an open-hearth steel furnace in eration of valves (not shown), the direction which my presentinvention is embodied. of flow through the furnace is reversed, the The plane of section is in Fig. II indicated port which had been serving as intake port by the line I-I. Fig. II is a view of the becomes the outgo port and the port which 80 same structure in vertical section, on the had been serving for the escape of gases beplane indicated at II-II, Fig. I. A certain comes the intake. Such reversal is incident movable member is in the two figures shown to the use of the regenerator. A regenerator in alternate operative positions. Figs. III is provided at or in association with each furand IV are views corresponding to Figs. I nace port; the outgoing hot gases sweep 85" and II and show the invention in application through the regenerator and heat to high tem;- to a furnace of different character. Fig. V perature the checkerwork of the regenerator, is a view in vertical section, on the plane and the checkerwork absorbs large stores of indicated at V-V, Fig. III. Figs. VI and heat. When the furnace is reversed, the air VII are views corresponding to Figs. I and on its way to the port (now become the in- 90' II and show an alternative arrangement. take port) passes through the regenerator and The furnace of Figs. I, II, VVI,.and VII is intakes up heat so stored in the checkerwork. tended to be operated with liquid fuel, such as By periodic reversal quantities of heat are tar or oil, or with pulverized coal dust borne at intervals stored alternately in each regenon a stream of compressed air; the furnace erator, and the stored quantities of heat are 95 of F igs. IIIV is intended to be operated taken up by the incoming air, rendering it with gaseous fuel. more effect-ive in the rapidity of combustion In the furnace. of Figs. I and II the walls of the fuel in the furnace chamber. of the furnace chamber are indicated at 1, the In the typical open-hearth furnace the same n hearth at 2, and the roof at 3. Ports 4 aruptakes and port which at one end admit the 100 .port may be slotted,

components of the combustible mixture to the furnace chamber, serve at the opposite end as the passageways for the escape of the products of combustion; and, as has been said, since the products of combustion are of vastly greater volume than the entering components of the combustible mixture, the designing of an efiicient port is an engineering problem of importance. rlhe problem is rendered moi1 difli-cult by the -fact that the outgoing gaseous products of combustion are exceedingly hot and in a condition to act most destructively on the masoniy walls of the port and passageways.

I provide an auxiliary passageway 7, opening through the floor of the port i and ar- `ranged in advance of the air uptakes 6--that is to say, nearer to the furnace chamberand leading to the regenerator. Conveniently, the passageway 7 unites with that from which the uptakes 6 rise, as is best shown in Fig. II. And I provide a cover-plate or slide 8 which, arranged immediately above the floor of the port, is movable in horizontal plane between the two positions illustrated in Figs. I and II. In the position shown in Fig. I the slide 8 overlies the passageway 7 and renders it ineffective; in the position shown in Fig. II the plate is withdrawn and the passageway 7 is open and effective. The proportions preferably are such that the slide 8 when withdrawn from passageway 7 still leaves the uptakes 6 open and unobstructed. The position of slide 8 as seen in Fig. I is its position at the intake end of the furnace; the passageway 7 is then ineffective; regenerated air is entering the port through uptakes 6 and is advancing to the furnace chainber to meet the fuel jetted through nozzle At the outgoing end of the furnace, slide t5 is withdrawn to the position shown in Fig. II, and the products of combustion ar streaming out, not through the passageways 6 merely, but through the great augmentationin escape which the passageway 7 af fords.

The slide S carries abutments Si of mason ry which form and define a constriction or throat in the port through which at the intake end the components of the combustible mixture stream in with increased velocity, to burn with increased intensity.

The slide is advantageously formed, as the drawings show, of a water-cooled marginal frame of metal carrying a low-arched vault of masonry. The circulation pipes 82 for water may be the members by means of which the slide is shifted. rEhe side-walls of the as indicated, to afford supports upon which slide 8 may rest and move; or (as particularly shown in Fig. V) the port walls may be formed with steps to aifordsuch support. llVater-cooled rails 83 may be provided as the immediate slide-- supporting members; and if the walls be slotted, the slots may be closed by aprons 13 of sheet metal, as indicated in Fig. I. The slide, constructed in the manner described, may readily carry the abutments 8l, which themselves also are formed of masonry.

The arrangement shown in Figs. VI and VII, otherwise identical with that of Figs. I and II, is distinguished in that the fuel nozzle 5a is made integral with the slide Sa and moves with it; so that when the slide is withdrawn to uncover at the outgoing end of the furnace the passageway 7, the nozzle 5a is withdrawn from the full sweep of the hot gases streaming through uptakes 6.

The furnace of Figs. III-T is intended for gaseous fuel. In place of a fuel nozzle, an uptake 9 for gas is provided. This uptake opens to the port in the vertical mid-plane of the structure and through a hood 13 delivers its stream into the port and in a direction f toward the furnace chamber. As in the other case, the air uptakes 6 are laterally arranged and the components of the combustible miX- ture meet as they enter the furnace chamber and the flame springs from the port and flows through the chamber. In this case, ordinarily, the gas as well as the air is heated on its approach to the furnace, and to that end a second pair of regenerators is provided, in which the gas is preheated. The outgoing hot products of combustion fiow in divided streams through both air and gas rcgenerators.

In this c. se the gas uptake 9 at the outlet end of the furnace, as well as the air uptakes 6, is advantageously kept open for the outflow of the products of combustion. In place of a single passageway 8 extending across the entire width of the port two such passageways 10 are advantageously provided, symmetrically arranged on opposite sides of the vertical mid-plane of the structure, and two slides l1 are provided, one associated with each of the passageways 10. The slides 1l are severally built and operated in the manner already described. They may severally carry abutments l2 which shall co-operate in the manner already described. Figs. III and V show the slides il in the positions they oc'- cupy at the intake end of the furnace; Fig. IV shows them in the position which they occupy at the outgoing end. Air and gas stream in through uptakes 6 and 9 and enter the furnace chamber through the gullet formed by abutmcnts 12, l2; the products of combustion escape through passageways 9 and 10. The abutments 12 being then withdrawn, the escape of gases is not hindered by a gullet. lVhether the slides 11 when withdrawn effect closure of uptakes 6 is a matter of proportioning of parts. A structure and a procedure such as to effect alternate closure of the uptakes 6 may or may not be resorted to. as circumstances dictate.

The slide 8 (ll, l1) is shifted, in co-ordination with the reversal of the furnace, to effect the ends described.

In the operation of the furnace described the products of combustion stream from the furnace chamber through the passageways which open through the floor of the port, with few and slight swirls and eddies and with a minimum of erosion of wall structure.

I claim as my invention:

l. In an open-hearth metallurgical furnace of reversing type the combination with a furnace chamber of duplicate ports at opposite ends thereof, an uptake opening through the floor of the port in a portion remote from the furnace chamber, a passageway opening through the floor of the port in a portion adjacent to the furnace chamber, a closure for said passageway movable within the port from a position of closure above said passageway to a position remote therefrom, and a gullet-forming abutment borne by said closure.

2. In an open-hearth metallurgical furnace of reversing type the combination with a furnace chamber of duplicate ports at opposite ends thereof, an uptake opening through the Hoor of the port in a portion remote from the furnace chamber, a passageway opening through the floor of the port in a portion adjacent to the furnace chamber, and a closure for said passageway movable within the port from a position of closure above said passageway to a position remote therefrom, the interval at which the openings through the lioor of the port to the said uptake and to the said passageway stand apart being as great as the width of said closure.

3. In an open-hearth metallurgical furnace of reversing type the combination with a furnace chamber of duplicate ports at opposite ends thereof, an uptake opening through the floor of the port in a position remote from the furnace chamber, a passage opening through the floor ofthe port in a position adjacent to the furnace chamber, a slide movable within the port from a position of closure above said passage to a position remote therefrom, and a fuel nozzle mounted integrally with and movable in unison with said slide from active to inactive position.

4. In an open-hearth metallurgical furnace of reversing type the combination with the furnace chamber of duplicate ports at opposite ends thereof, an uptake passage opening through the ioor of the port, a slide movable in the direction of the length ofthe furnace upon the floor of said port, said slide bearing a gullet-forming abutment standing inthe assembly athwart the port, said slide in its advanced position coveringsaid passageway and closing access of the components of the combustible mixtureV to the furnace chamber eXcept through such gullet, and the said slide when in withdrawn position hereunto set 

